Ответы на рабочий лист исследование магнитных жидкостей
Ответы на рабочий лист исследование магнитных жидкостей.docx
Magic Magnetic Fluid
Liquid Magnets Worksheet – Answers
Part 1: Concepts
1.How can a Liquid be
dispersed in liquid to form a colloid OR
Paramagnetic salt liquids
2.What type of magnetic
material (paramagnetic, diamagnetic, or ferromagnetic) would be best for making
a liquid magnet? Explain the fundamental differences between the three
classifications of magnets and why you would use one over the other.
ferromagnetic material because of the large magnetic permeability and
spontaneous alignment of domains when subjected to external magnetic field.
when exposed to external magnetic field an induced dipole moment opposes the
external magnetic field lowering the net magnetic field.
Permanent dipole moments align with external magnetic field but are opposed by
thermal agitations reducing the attraction.
Spontaneous alignment of magnetic moment of each atom forming domains which are
randomly oriented when in an unmagnetized state.
The picture below
depicts what is going on in your test tube. Although you cannot see the
particles, they are there. Fill in the three spaces in the magnified picture.
Below the picture write the purpose of each labeled component.
Fluid: What transports magnetic nanoparticles when
not induced by a magnetic field.
Particle: What provides the magnetic attraction when
exposed to an external magnetic field?
Surfactant: Chemical that helps
spread magnetic particles apart and attach to carrier liquid.
boxes below, draw your observations of the ferrofluid when exposed to the
external magnet and when not exposed.
Drawings will vary.
would you describe the ferrofluid when it is NOT exposed to an external magnet?
The fluid should be liquid like and free
flowing. Most observations show a “blob” of liquid with no definite shape from
a top view.
would you describe the ferrofluid when it is exposed to an external magnet?
Explain how the physical properties of the fluid changed.
The “blob” of liquid forms a dome shape
(side view) with or without spikes (depending on MICR toner and magnet
strength). Liquid viscosity is greatly increased and does not free flow.
Typical observations and drawings consist of a dome shape mass with a
characteristic height with or without spikes.
space provided below draw the magnetic domains associated with nanoparticles.
Compare this behavior to traditional magnetic materials.
Traditional Bulk Magnetic Material: Figure
shows a gradual alignment of domains with direction of magnet as a magnetic
field is applied in two dimensions. Three dimensional alignments of domains
occur in real materials. KEY: bulk material (polycrystalline) will have
numerous domains as indicated above.
Individual nanoparticles align with magnetic
field. Result is a three dimensional depiction of magnetic field directions and
varying strengths. KEY: Single domain arrow is characteristic of the
nanoparticle because of the particle size can only contain one domain.
ferrofluid materials behave differently than bulk magnetic materials?
Ferromagnetic particles within the fluid
specifically align with the external magnetic fluid making a dome shape with or
without spikes. The spikes are a result of the strong magnetic lines in that
particular direction and are present when nanoparticles are strong ferromagnetic
particles and the external field is large enough. The liquid carrier fluid
allows for shape changes to occur easily under various external magnetic
Bulk magnetic materials are solid, rigid
structures that do not change shape under external magnetic fields.
might you use this type of technology or property manipulation? Name 3
applications with a 1-2 sentence explanation.
Drug Delivery systems: Targeted delivery by
developing magnetic drug compatible with human systems where delivery path is
guided by a controlled magnetic field.
Magnetic tracking beacon: Inject fluids
where a magnetic signature could be detected under an applied magnetic field.
Cooling systems: utilize convection cooling
from liquid to achieve higher heat transfer in electronic systems.
This question is intended
to stimulate out-of-box thinking.
Magic Magnetic Fluid Activity –
Component 3: Surfactant: Chemical that helps spread magnetic particles apart and attach to carrier liquid
Individual nanoparticles align with magnetic field